package com.itheima.day04;

import java.util.Scanner;

public class demo07 {
    public static void main(String[] args) {
        int[] arr = {19, 28, 37, 46, 50};
        Scanner sc = new Scanner(System.in);
        int num = Integer.parseInt(sc.nextLine());
        int temp = -1;
        for (int i = 0; i < arr.length; i++) {
            if (num == arr[i]) {
                temp = i;
            }
        }
        System.out.println(temp);
    }
}
